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Respiration
Fig. 9-6-3
Electrons carried
via NADH and
FADH2
Electrons
carried
via NADH
Citric
acid
cycle
Glycolysis
Pyruvate
Glucose
Oxidative
phosphorylation:
electron transport
and
chemiosmosis
Mitochondrion
Cytosol
ATP
ATP
ATP
Substrate-level
phosphorylation
Substrate-level
phosphorylation
Oxidative
phosphorylation
Cellular Respiration
• Cellular respiration includes both aerobic
and anaerobic respiration but is often used
to refer to aerobic respiration
• Glycolysis – anaerobic
• Kreb’s Cycle and Electron Transport Chain
– Take Place in mitochondria
– Aerobic
ATP Yield
• Process
– Glycolysis
– Kreb’s Cycle
– Electron Transport
Chain
• Net ATP Yield
–2
–2
– 32-34
Glycolysis (animation 2)
1) Glucose is phosphorylated by
hexokinase
– Which transfers P from ATP glucose
producing…
– Glucose 6-phosphate
2) The enzyme phosphoisomerase
transforms the molecule from glucose 6phosphate to fructose 6-phosphate
– Structural change from hexose to pentose
Fig. 9-9-1
Glucose
ATP
1
Hexokinase
ADP
Glucose
Glucose-6-phosphate
ATP
1
Hexokinase
ADP
Glucose-6-phosphate
Glycolysis
1) Glucose is phosphorylated by
hexokinase
– Which transfers P from ATP glucose
producing…
– Glucose 6-phosphate
2) The enzyme phosphoisomerase
transforms the molecule from glucose 6phosphate to fructose 6-phosphate
– Structural change from hexose to pentose
Fig. 9-9-2
Glucose
ATP
1
Hexokinase
ADP
Glucose-6-phosphate
2
Phosphoglucoisomerase
Fructose-6-phosphate
Glucose-6-phosphate
2
Phosphoglucoisomerase
Fructose-6-phosphate
3) The enzyme phosphofructokinase
transfers a phosphate group from ATP to
form Fructose 1,6-bisphosphate
– 2 Phosphates attached molecule ready to split
4) The enzyme adolase breaks the fructose
1,6-bisphosphate into two 3 carbon
molecules – G3P and Dihydroxyacetone
phosphate
5) Isomerase converts the previous 2
molecules into G3P – Glyceraldehyde 3Phosphate
Fig. 9-9-3
Glucose
ATP
1
Hexokinase
ADP
Fructose-6-phosphate
Glucose-6-phosphate
2
Phosphoglucoisomerase
ATP
3
Phosphofructokinase
Fructose-6-phosphate
ATP
3
Phosphofructokinase
ADP
ADP
Fructose1, 6-bisphosphate
Fructose1, 6-bisphosphate
3) The enzyme phosphofructokinase
transfers a phosphate group from ATP to
form Fructose 1,6-bisphosphate
– 2 Phosphates attached molecule ready to split
4) The enzyme adolase breaks the fructose
1,6-bisphosphate into two 3 carbon
molecules – G3P and Dihydroxyacetone
phosphate
5) Isomerase converts the previous 2
molecules into G3P – Glyceraldehyde 3Phosphate
Fig. 9-9-4
Glucose
ATP
1
Hexokinase
ADP
Glucose-6-phosphate
2
Phosphoglucoisomerase
Fructose1, 6-bisphosphate
4
Fructose-6-phosphate
ATP
Aldolase
3
Phosphofructokinase
ADP
5
Isomerase
Fructose1, 6-bisphosphate
4
Aldolase
5
Isomerase
Dihydroxyacetone
phosphate
Dihydroxyacetone
phosphate
Glyceraldehyde3-phosphate
Glyceraldehyde3-phosphate
Note to class- I am slowing removing some
of the names of the molecules you do not
need to know See Handout 4 names
6) The two G3P molecules gain P and are
oxidized, forming 2NADH + 2H+
7) Phosphoglycerokinase catalyzes P from
the molecule forming 2 ATP (substrate
level phosphorylation)
8) The enzyme phosphoglycermutase
changes the position of the phosphate
group
Fig. 9-9-5
2 NAD+
2 NADH
+ 2 H+
6
Triose phosphate
dehydrogenase
2 Pi
2 1, 3-Bisphosphoglycerate
Glyceraldehyde3-phosphate
2 NAD+
2 NADH
6
Triose phosphate
dehydrogenase
2 Pi
+ 2 H+
2 1, 3-Bisphosphoglycerate
Note to class- I am slowing removing some
of the names of the molecules you do not
need to know See Handout 4 names
6) The two G3P molecules gain P and are
oxidized, forming 2NADH + 2H+
7) Phosphoglycerokinase catalyzes P from
the molecule forming 2 ATP (substrate
level phosphorylation)
8) The enzyme phosphoglycermutase
changes the position of the phosphate
group
Fig. 9-9-6
2 NAD+
2 NADH
+ 2 H+
6
Triose phosphate
dehydrogenase
2 Pi
2 1, 3-Bisphosphoglycerate
2 ADP
7
Phosphoglycerokinase
2 ATP
2 1, 3-Bisphosphoglycerate
2 ADP
2
3-Phosphoglycerate
2 ATP
2
7
Phosphoglycerokinase
3-Phosphoglycerate
Note to class- I am slowing removing some
of the names of the molecules you do not
need to know See Handout 4 names
6) The two G3P molecules gain P and are
oxidized, forming 2NADH + 2H+
7) Phosphoglycerokinase catalyzes P from
the molecule forming 2 ATP (substrate
level phosphorylation)
8) The enzyme phosphoglycermutase
changes the position of the phosphate
group
Fig. 9-9-7
2 NAD+
2 NADH
+ 2 H+
6
Triose phosphate
dehydrogenase
2 Pi
2 1, 3-Bisphosphoglycerate
2 ADP
7 Phosphoglycerokinase
2 ATP
2
3-Phosphoglycerate
8
2
3-Phosphoglycerate
Phosphoglyceromutase
2
8
Phosphoglyceromutase
2-Phosphoglycerate
2
2-Phosphoglycerate
9) Enolase removes water from both carbon
chains
10) The enzyme pyruvate kinase mediates
the transfer of phosphate from
phosphoenolpyruvate to 2ADP forming
to 2ATP- the final molecule is PYRUVATE
-2 Pyruvates
Fig. 9-9-8
2 NAD+
2 NADH
+ 2 H+
6
Triose phosphate
dehydrogenase
2 Pi
2 1, 3-Bisphosphoglycerate
2 ADP
7 Phosphoglycerokinase
2 ATP
2
3-Phosphoglycerate
2
2-Phosphoglycerate
8
Phosphoglyceromutase
9
2
2 H2O
2-Phosphoglycerate
Enolase
9
Enolase
2 H2O
2
Phosphoenolpyruvate
2
Phosphoenolpyruvate
9) Enolase removes water from both carbon
chains
10) The enzyme pyruvate kinase mediates
the transfer of phosphate from
phosphoenolpyruvate to 2ADP forming
to 2ATP- the final molecule is PYRUVATE
-2 Pyruvates
Fig. 9-9-9
2 NAD+
6
Triose phosphate
dehydrogenase
2 Pi
2 NADH
+ 2 H+
2 1, 3-Bisphosphoglycerate
2 ADP
7 Phosphoglycerokinase
2 ATP
2
Phosphoenolpyruvate
2 ADP
2
3-Phosphoglycerate
8
Phosphoglyceromutase
2 ATP
2
10
Pyruvate
kinase
2-Phosphoglycerate
9
2 H2O
Enolase
2 Phosphoenolpyruvate
2 ADP
10
Pyruvate kinase
2 ATP
2
2
Pyruvate
Pyruvate
Products of Glycolysis
• 2 ATP NET (4 ATP gross)
• 2 Pyruvates (pyruvic acid)
• 2 NADH
Fermentation
•
•
•
•
Anaerobic process
Regeneration of NAD+
Produces waste
1)Lactic Acid – Prokaryotes and Muscle Cells
– Pyruvate + 2H+ + NADH  Lactic Acid + NAD+
• 2) Alcohol – Yeast (fungus)
– Pyruvate + 2H+ + NADH  Ethanol + CO2 + NAD+
• 2 Steps – CO2 is removed and then NADH is used to
convert molecule to Ethanol
Fig. 9-18a
2 ADP + 2 P i
Glucose
2 ATP
Glycolysis
2 Pyruvate
2 NAD+
2 Ethanol
(a) Alcohol fermentation
2 NADH
+ 2 H+
2 CO2
2 Acetaldehyde
Fig. 9-18b
2 ADP + 2 P i
Glucose
2 ATP
Glycolysis
2 NAD+
2 NADH
+ 2 H+
2 Pyruvate
2 Lactate
(b) Lactic acid fermentation
Mitochondrial Structure
Cytoplasm
C C
ATP Synthase
C
Kreb Cycle (Citric Acid Cycle)
• Occurs in the mitochondrial matrix
• Occurs 2X per 1 Glucose molecule
– 2 Pyruvates
Fig. 9-10
CYTOSOL
MITOCHONDRION
NAD+
NADH + H+
2
1
Pyruvate
Transport protein
3
CO2
Coenzyme A
Acetyl CoA
Kreb Cycle - Draw on Board
Fig. 9-12-8
Acetyl CoA
CoA—SH
NADH
+H+
H2O
1
NAD+
8
Oxaloacetate
2
Malate
Citrate
Isocitrate
NAD+
Citric
acid
cycle
7
H2O
NADH
+ H+
3
CO2
Fumarate
CoA—SH
6
-Ketoglutarate
4
CoA—SH
5
FADH2
NAD+
FAD
Succinate
GTP GDP
ADP
ATP
Pi
Succinyl
CoA
NADH
+ H+
CO2
– Acetyl CoA formation generates 1 NADH
• 2 per glucose
– The cycle oxidizes organic fuel derived from
pyruvate, generating 1 ATP, 3 NADH, and 1
FADH2 per turn
• 2,6,2 per glucose
– 2,8,2
Electron Transport Chain
• Takes place along the inner membrane of
mitochondria
– Uses NADH and FADH2
– Oxidative Phosphorylation = ETC + chemiosmosis
Fig. 9-16
H+
H+
H+
H+
Protein complex
of electron
carriers
Cyt c
V
Q


ATP
synthase

FADH2
NADH
2 H+ + 1/2O2
H2O
FAD
NAD+
ADP + P i
(carrying electrons
from food)
ATP
H+
1 Electron transport chain
Oxidative phosphorylation
2 Chemiosmosis
ETC
•
NADH and FADH2 (produced during
krebs cycle) are stored in the matrix
1. NADH releases protons and electrons on
the matrix side
A. Protons are pumped into the
intermembrance space
B. Electrons are transported across the
membrane using ubiquinone (coenzyme Q)
and cytochrome C
ETC Cont
2. FADH2 drops protons and electrons at
ubiquinone
–
See A and B on previous slide
3. Protons diffuse through ATP synthase to
produce 32-34 ATPs (oxidative
phosphorylation)
4. The cytochrome oxidative complex  O2 +
electron + H+ yield to form H2O
Oxygen is the final electron acceptor in cellular
respiration
• The proton gradient is produced by the
movement of electrons along the electron
transport chain.
• Several chain molecules can use the
exergonic flow of electrons to pump H+
from the matrix to the intermembrane
space.
– This concentration of H+ is the protonmotive force.
• The ATP synthase molecules are the only
place that will allow H+ to diffuse back to
the matrix.
• This exergonic flow of H+ is used by the
enzyme to generate ATP.
• This coupling of the redox reactions of the
electron transport chain to ATP synthesis is
called chemiosmosis.
• How efficient is respiration in generating
ATP?
– Complete oxidation of glucose releases 686
kcal per mole.
– Formation of each ATP requires at least 7.3
kcal/mole.
– Efficiency of respiration is 7.3 kcal/mole x 38
ATP/glucose/686 kcal/mole glucose = 40%.
– The other approximately 60% is lost as heat.
Cellular Respiration Overview